What bothered North Korea so much about Laura Ling and Euna Lee?

Monday's sentencing of two US journalists to 12 years for trespassing is the latest in a streak of unusually defiant behavior, even by North Korean standards.

Laura Ling and Euna Lee had been reporting on North Korean human rights abuses, a topic that upsets North Korean officials. In particular they were focusing on North Korean refugee women who flee the country to China.

Several years ago Ling's older sister, Laura Ling, posing as a member of a medical team, did a National Geographic documentary in North Korea with a hidden camera. The film provided devastating insights into life in the North and the level of thought control imposed by the regime.

It is still not clear if North Korean authorities picked up the film Laura Ling and Euna Lee had already shot, and was contained on it. The producer and cameraman on the project, Mitch Koss, who escaped has not revealed publicly what he saw or whether he got away with his equipment and videotape.